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Does breathing 100% oxygen cause health issues?
When flying at high altitudes in an unpressurized plane, you use portable oxygen tanks to prevent hypoxia and other altitude-related symptoms. but does this 100% pure oxygen cause health issues when flying at high altitude?

It should be noted that you are not breathing in 100% O2, you are supplementing the lack of O2 at altitude with additional O2. Very rarely would you breathe pure O2, it's typically mixed (using a rebreather, diluter, or cannula) with cabin air.

"Love is like oxygen - you get too much, you get too high"

If you consider a flash fire a health issue, then yes. However, it wasn't due to breathing the pure O2.

When we discuss a mixture of gasses, it's often useful to compute the pressure of each component separately. This is called the "partial pressure" of that component. For instance, oxygen composes only 21% of our atmosphere, so at sea level (1013 hPa), the partial pressure of oxygen would be about 213 hPa.
If you have a semipermeable membrane (such as, for instance, the tissue of a human lung), it's the partial pressure of each component of the mixture that determines the flow of that particular component. Oxygen flows into the blood from the air because the partial pressure of oxygen in the blood is less than the partial pressure of oxygen in the air.
Thus, as the total air pressure goes down, the percentage of oxygen it contains can be increased without affecting the body. If you were breathing pure oxygen at 213 hPa, your blood would have the same amount of oxygen as if you were breathing normal sea-level air. Of course, it's dangerous to go that low for reasons other than lack of oxygen, but the human body is pretty resilient, so as long as you get close, you can safely breathe pure oxygen indefinitely.
For instance, astronauts who flew on Gemini VII spent two weeks breathing pure oxygen at a maximum of 6 psi (414 hPa) and were perfectly fine. That's roughly the ambient air pressure at 20,000 feet. However, Gemini missions had strict limits on how long the astronauts could stay in the capsule before launch, because at that point they were breathing pure oxygen at sea-level pressures, which can cause health concerns.

About the physiology of breathing: one thing lowering the partial pressure of oxygen while breathing in, is that as the air enters the lungs, it instantly becomes saturated with moisture. A 100% "shot" of oxygen will not be 100% anymore when it enters the lungs. This moisture saturation is one major factor in development of hypoxia at higher altitudes.

And going the other way, deep sea divers have to decrease the amount of oxygen in their breathing mixture to avoid oxygen toxicity and longer-term damage.

So if you breath it at sea level pressures then it becomes a health risk?

@Boeing787 Yes, it does.

@Boeing787 Breathing pure oxygen at sea level pressure is no health risk when done for 1 or 2 hours, but for 10 and more hours it is a health risk.

Yes...
but not predictably, and (almost certainly) not seriously. If you're worried for yourself and you're not already dead and not doing any crazy maneuvers, it is vanishingly unlikely that you need to worry about health effects of pure oxygen. Before focusing on composition control, focus on fixing your sleep, hydration and seated posture.

Specific to aviation, the biggest issue is that it exacerbates atelectasis. Your lungs are made up of many tiny air-sacks called alveoli. These are held open by the ambient air pressure in your lungs, while surface tension of the water lining your lungs naturally tries to squeeze them closed*. Oxygen goes through the walls of your lungs fairly readily; nitrogen does not. If you have actual pure O2 in an alveolus, it will collapse very easily. When a small fraction of alveoli collapse, it's called atelectasis (when most alveoli do it at the same time, it's a "collapsed lung"). You obviously won't get pure O2 after everything mixes together, but the closer you get, the less resistant your lungs are to atelectasis.
Atelectasis isn't that bad in isolation. It can be uncomfortable, and makes you work harder for a less effective result when you breath, but it's not usually a major problem. Also, it usually resolves itself with any brief, transient overpressure (i.e. it goes away if you cough). However, if you're already borderline on breathing, it's not a great addition to the mix.
That's probably fine for large passenger aircraft. For jets doing maneuvers, it is much less fine: another major contributor to atelectasis is g-force. F-22 pilots knew of a phenomenon they called "Raptor cough", where they would always need to cough after pulling positive-g maneuvers.
You can see where this is going, and indeed atelectasis was identified as a contributing factor on the US Navy's physiological episode epidemic a few years back.**
Although the NASA report highlighted the issue, it was a known design constraint for a while ahead of time. you can search "MIL-STD-3050" to get an idea of how the DoD plans to approach new designs. (3050 is a garbage spec because it's poorly written, but the underlying approaches are mostly solid).

The other potentially major issue is not about pure oxygen per se, and definitely not relevant to tanked oxygen: there is some evidence that rapid swings in breathing gas composition can induce physiologically Bad Things. Unless you are deliberately monkeying with the valves for a while, that's only going to be applicable to OBOGS, and only under some circumstances.

Otherwise, the dangers of pure O2 in aviation are the same as when you're sitting in your living room:

It's an oxidizer and thus promotes rapid combustion of flammable materials.
It can dry you out quickly.
There is at least one very rare condition where pure O2 will make you go hypercapnic and kill you.

For the more exotic dangers, you're going to want anaesthesiologists to answer. Outside of aviation, the only time you're likely to be on pure O2 is under general sedation, and, conveniently, that's also the time when there is a doctor very closely monitoring you (difficult to do in flight).

I am summarizing and simplifying at several points above, because the detailed interactions are complicated but don’t change the behavior. If you want a solid grounding in the details of how lungs work, find a copy of Guyton & Hall, Textbook of Medical Physiology. Very readable, and enough technical detail to engineer against.

*You have a special coating that floats on top of the water lining your lungs: "pulmonary surfactant" (i.e. "lung gunk"). It does a lot and is poorly understood. One major thing it does is reduce the surface tension which is trying to collapse your alveoli by about 60%. That collapsing force is proportional to surface tension and to the square of alveolar radius. Developing babies have smaller alveoli and start making surfactant around week 28. That's why week 28 is when premature birth goes from really, really bad to just regular bad.
** Search "NESC report on F/A-18, E/A-18 physiological episodes" to find NASA's report on the subject. I couldn't find a single authoritative document source, but there are copies of the thing all over.

"Oxygen goes through the walls of your lungs fairly readily; nitrogen does not." This is wrong, nitrogen does go from the lungs into the body and may cause decompression sickness. This is a problem for scuba divers but also for military pilots ascending very fast without a pressurized cabin.

@Uwe I am comfortable describing equalizing on the order of tenths of a second as “fairly readily” and equalizing on the order of tens of minutes to hours as “not fairly readily”.

Is that equalizing difference really a lung surface effect? AFAICT the reason oxygen distributes so fast is because hemoglobin in blood is a far more effective carrier. And of course, the third important gas (CO2) is carried as H2CO3

@MSalters it’s a distinction without a difference here. The liquid side isn’t even a partial pressure anyway, because that only applies to gas. But the oxygen and nitrogen move bi-directionally through your lung surface based on chemical gradients, and oxygen flows out of the alveoli much more readily (largely because of what happens after, but still)

FWIW, "G-cough" isn't new or unique to the F-22 Raptor...

@MichaelHall agreed. That’s where it got a lot of publicity though (example: https://abcnews.go.com/Blotter/22-fighter-pilots-battle-mysterious-raptor-cough/story?id=16303962 ), which is why I pointed to it.

"you're not already dead and not doing any crazy maneuvers" So can I be alive and doing crazy maneuvers, or must I be dead as well? ps If I am already dead, my concern about O2 is limited.

Depending on environment pressure and duration, breathing pure oxygen may cause health issues. But health issues are more a problem during SCUBA diving and hyperbaric chambers than high altitude flying.
Oxygen partial pressures of above about 0.5 bar may cause lung problems after one to several days.
Above about 1.2 to 1.5 bar breathing of pure oxygen may cause spasm and loss of consciousness after some ten minutes. So this is not possible during aviation.
At partial pressures and durations possible when flying health issues caused by pure oxygen are impossible for persons healthy to fly as a passenger or a pilot.

There is some evidence $^{[1]}$ to suggest that breathing high concentration oxygen can lead to lung damage over the long term as a result of the buildup of reactive oxygen species in lung tissues. This is linked to the development of lung cancer.
In terms of absolute risk this is likely minimal compared to the increased exposure to cosmic ionising radiation experienced at altitude. As such it's not really relevant, but it is interesting.


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Can an airplane fly with on-off control surfaces?
I understand that, at least for remote-controlled model planes, the control surfaces can point to a range of angles, say, from $-30^\circ$ degrees to $30^\circ$. My questions are:

Would the same airplane work if the control surfaces can only point to, say, $-30^\circ$, $0^\circ$, $30^\circ$.
If I rapidly switch the surface on ($0^\circ$) and off ($30^\circ$) like in pulse-width modulation (PWM). Is that equivalent to having the control surface pointing at $15^\circ$?

Early RC model airplanes worked that way. Just make sure you don't switch the control surface with anything close to a flutter frequency. The effect is not exactly equivalent, but close enough for coarse remote control.

Interestingly, the control surfaces of the GBU-12 Paveway II laser-guided bomb are actuated in such a bang-bang fashion.

Not really a full answer, but if you do that to the rudder of an Airbus A300, the vertical stabilizer breaks off.

@qqjkztd Somewhat like the way most planes aren't limited to when they land in Sioux City?

@PeterKämpf - it's nice to know someone else remembers the Good/Bad Old Days too. :-)

@PeterKämpf - Yes, it was called "galloping ghost". https://youtu.be/xBSRmlIGSWQ

Although not aircraft, but spacecraft is pretty much on/off control.

@TomCarpenter: Only if you do it in alternating directions several times in a row.

Depends what you're talking about.   Do you mean for the flight controls to actually slam all the way to stop, then center, then slam to stop, etc., violently slamming the aircraft around? (Terrible for fuel economy by the way, and hard on everything else).
Or do you mean to use PWM to select an intermediate position? E.g. 50% duty cycle gives you stable 15 degree rudder?
The trick is to put damping in the operating mechanism, and PWM at a frequency fast enough for the damping to do its job: before the surface physically gets a chance to move, the PWM reverses.  The PWM is too fast to wobble the surfaces.
Then also either add some spring resistance so deflection will be predictable for a given duty cycle, or have an analog position sensor educating the PWM as to its effects. Air resistance varies with speed, and without something to equalize it, surfaces at a given duty cycle will deflect different amounts for different speeds. Of course, that could be made a "feature": as DJ319 points out, you actually want less deflection at higher speeds.

Theoretically it could work that way. A maneuver that needs a certain control surface deflection for a certain amount of time could be done with full 30 degree deflection in a shorter time.
Fine control and trimming would be more difficult. Small adjustments would require a very short time at full deflection. Control laws would have to take into account the step response of the system to determine how quickly the surface can reach the full deflection. By pulsing a deflection command like with PWM, you could determine a modulation that would keep the surface near some nominal deflection.
For an RC plane's systems this may be fine. With larger aircraft you would need to consider the effect of these large inputs into the control system, and structural effects, including whether 30 degree deflection is possible in the current flight conditions.

Very early model remote controls in the 1940s and 50s worked that way. Later, improved models would stress their "proportional" control to distinguish themselves from the earlier models. Just like temporal dithering is used for pixels, short pulses of full deflections can be used for control. There is even a special field of control theory for this.

Also: from the passengers point of view, that would probably be very uncomfortable!

Another issue is that response to control deflection is non linear. The response to a sudden large deflection of a control surface is not just larger than the response to a small one. Turbulence and non-Newtonian Dynamics can make it very different.

Use a keyboard as your primary controller. KEYDOWN = control on. KEYUP = control off. And yeah it's not a smooth ride.

I once had a very cheap electric ducted fan styrofoam RC plane that I found for sale at Woolworths sometime in the 90s that had "bang bang" flight control surfaces and throttle.  In lieu of servos, it had a very light, weak solenoid with the control rod as its core.
I was a novice, but was able to get it to 'fly' a maximum distance of 20ft, bank either left or right as commanded, descend steeply or slightly less steeply by blipping the elevator, but never climb without instantly rolling into a knife edge dive.  More of a slightly delayed crash than flight.  But someone believed in the design enough to market and sell it.

As many people have mentioned examples of where it has been used. I would just like to mention that on full scale aircraft the stresses involved in deflecting control surfaces to maximum deflection at cruise speeds (even for a fraction of a second) would probably result in structural failure. In addition to this those kinds of deflections would result in huge g-forces for the crew and any passengers possibly resulting in black outs or red outs.
I would then suggest that something like this could only be used for unmanned craft. Unless the max min values scaled with the aircraft velocity. For example at cruise instead of +-30 degrees of deflection you would have +- 10 to 15 degrees.

This has been done in WWII glide-bomb systems. However, since the idea isn't widely used, it presumably has practical disadvantages.

Yes, it could. The first guided bomb, the German Fritz X developed during WW2, used such a setup. They refined it a bit by oscillating the control surface from neutral to deflection rapidly, so that it wasn't a pure on/off control input.
This was a clever way to get around the limitations of tech of that day, that they weren't able to develop a porportionally adjustable control surface. They could, however, change the oscillation rate with the analog electronics they had available, which in effect gave some proportional control. The faster the surface oscillated, the greater the control input.
The Fritz X was very successful, sinking the Italian battleship Roma, and damaging several allied ships. It fell into disuse when the allies got full control of the air - the Fritz X was visually guided, and required a bomber to remain near the target while the bomb pilot guided it in.

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How can pilots get other pilots' attention without the use of radio
In this video, a pilot makes the embarrassing mistake of announcing the passengers on an active frequency. During the video, other pilots are apparently trying to get his attention by sending some sort of beeping noise. What are they doing to get his attention?
https://youtube.com/shorts/pTGyDArfS2Y?feature=share

How can a plane communicate w/o the use of RF? Morse code with the landing lights? afaik, the radio, datalink, ACARS, and everyone's cell phone don't work w/o RF. On a sat phone, you could at least receive maybe... somehow "radio waves are used to send the signal up to the satellite, while the satellite uses its own technology to relay the signal back down to the user." which cuts the corner into microwaves but not really by that much. As long as w/e the interference is, isn't affecting "the top end of the ultra high frequency" (L) band.

Anybody keying the mic on the same frequency the unfortunate PA-over-the-radio pilot is transmitting on is accomplishing nothing productive whatsoever, and anybody with access to such a microphone ought to be smart enough to realize it.  When a radio is transmitting on a frequency, it isn't receiving on that frequency (since the only thing the receiver could possibly hear is your own transmission), and so anybody keying their mic on top of his isn't being heard by the unfortunate pilot who is making his PA over the radio. (Nor is their transmission likely to be intelligible to anyone else on the frequency.)
The "beeping" or squealing noise heard in the video is simply what's received (i.e. by a third radio) when two transmitters are both transmitting on the same frequency.  Neither station that's transmitting hears it.
(There's those who have, and those who haven't yet, but if you make enough PA's, sooner or later one will go out over the radio.)
If there is a second frequency that the PA'ing pilot is listening to, it's possible that a message on that frequency might be heard, but that's not always particularly likely.
The best defense I've found against this situation is to NEVER listen to your flying partner's PA's -- don't have PA audio "on" when they're talking on it.  Then, if you do hear, "Ladies and gentlemen, we..." then look over at their comm panel & switch them off of COMM1 or COMM2 if that is in fact what's going on.
Nevertheless, "those who have, & those who will" still applies.

And there's the converse. I was on a flight where a pilot friend was in the jumpseat. The Capt made a PA and then left for the head (pre-9/11). My friend took the left seat and promptly replied to ATC over the PA. I got to call him out for it when we got to our destination.

There is no way to get a pilot’s attention while they are transmitting. ATC frequencies are “simplex” meaning once you start transmitting, all incoming reception is blocked. Any pilot or ATC should know it’s impossible to reach the offending pilot.
The beeps you hear are not other pilots or ATC trying to get the attention of the transmitting pilot. The beeps are feedback caused when two radios transmit at the same time. The simultaneous transmissions are probably other pilots or ground vehicles try to transmit over the offending pilot, hoping to reach ATC ground control.
One way to get a transmitting pilot’s attention is to use another radio frequency that the other pilot may be monitoring. Another option is using datalink or ACARS to send a text message to the flight deck.

At Dorval a few years ago, a Jazz FO gave the passenger briefing over comms channel selected to Ground instead of the PA. The ground controller responded with "What's the movie?".

Just a quibble: The beeps are actually a beat frequency, not feedback. Tone frequency is equal to the slight difference in frequency between the two radios transmitting. See SE Amateur Radio: https://ham.stackexchange.com/questions/14901/is-it-possible-to-have-multiple-people-talking-on-the-same-radio-channel-at-the#comment21365_14902

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F15 Startup Intake drop
So I’m aware that the F15 has intake Ramps that adjust to airspeed and AOA, in order to ensure that the airflow is entering the engine smoothly and not too fast. But why does the system drop the first intake ramp when the engine is starting up?
Why would it restrict airflow at idle power?

Picture link - http://form.univ-mosta.dz/?y=til-f-15-fighter-jets-air-intakes-are-variable-zz-2an4X3sL

Not sure I understand the question completely. Why not have it go ahead and drop to the take-off position at that time?  Or perhaps the question is why do the ramps lock in the up position at shut down?

Is it actually "necessary", or is that simply what you observe?  Perhaps it's just a byproduct of hydraulic pressure being available or not?

My guess it's to have the intake ramp aligned with the incoming flow during high-angle-of-attack situations like take-off and landing.

@ROIMaison This is what I have been thinking. I guess it’s just my odd mechanical obsession.

when the intake takes in supersonic air the engine may experience turbulence and hence get damaged. Hence, the inlets are responsible for turning the supersonic air into subsonic such that the engine is able to handle it. when the air goes supersonic the first ramp opens up, the second ramp converges to make sure the air reaching the engine goes subsonic and intern not damage. Similarly, when subsonic air enters, the first ramp converges as the second ramp opens up to allow for "increased" airflow. This helps prevent stalls during start up and/or overwhelm the engine.
Later on during flight both the ramps open up (during subsonic flow).
I hope this answers your question, much of this has been researched using Quora and Google:
https://www.quora.com/Why-are-F15-jet-air-intakes-pointing-a-bit-downwards-and-not-straight
I did find it hard to understand so I've simplified it in my own words.

You really just added detail to what the OP explained that they already knew in the first sentence.

yes, but I added more details to solve his question

Thanks for the extra info!! I’ve visited the page before but didn’t really find anything about the reason for them coming down during startup.

@Boeing787 Glad I could help!


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Why does Qatar Airways fly over Syria and Iraq?
I saw on Flightradar that Qatar Airways still fly over Syria and Iraq. Why do they think that airspace is safe? I dont want to have to worry about my plane being shot out of the sky on my trip.

Related

OPSGROUP had some interesting thoughts on this in September after Syria shot down a Russian Ilyushin IL-20M transport 50nm away from a well-traveled airway east of Cyprus: Why are we still flying airline passengers over war zones?

They are trying to save themselves money, and their customers time.
First of all, why do the planes follow that route?  From your comments, you are going from Philly to Doha.

You might want to take a look at great circle routes to see why the planes are coming into Doha from that direction.  The Great Circle route depicted goes right through Syria and Iraq: it's the most efficient way to get there. Beyond that, Qatar has a few limitations that other airliners don't have, in that region, due to some diplomatic problems with their neighbors, who won't let them overfly their airspace: Saudi, Egyptian, and UAE airspace for the time being is closed to them.  (thanks @reirab)
Diversions cost money
Some typical diversions in that region are well spelled out in this article in the Economist.
What you may be seeing is that, for some flights that pass over the region, rather than landing within the region, they are accepting the risk that their airliners at 30,000+ feet might, maybe, get targeted on a really bad day (see the Malaysian Airlines flight shot down over the Ukraine a few years ago (MH 17)). But the odds of that are very low.  They most likely will not be disturbed.  (Or so a risk management case can be made).  A more conservative view of risk is offered here, in an Ops Group posting from September of 2018.  (Thanks to @ZachLipton for the link).
Route diversions have very real fuel costs, and costs in time.

Image from the Economist, Oct 20, 2018 edition.
The article mostly addressed flight into Lebanon by Middle Eastern carriers.  Flying into Beirut is of higher risk since the aircraft have to come down through the risky / war zone airspace for final landing, but it's instructive to illustrate how costs go up when more direct routing can't be taken due to safety precautions around conflict zones.

But for years the airspace over Syria has been crowded with warplanes. The Gulf airlines no longer use it. Instead Emirates, the flag carrier of Dubai, detours across Saudi Arabia and Egypt, adding 700 km to the trip.  The journey takes even longer on Qatar Airways, which was barred from Saudi airspace after a dispute between the Gulf countries erupted last year. Its route from Doha to Beirut resembles a crook: north over Iran, west across Turkey and south down the coast. What should be a 1,825km flight drags on for 2,865km. {snip}
  For travellers this is a nuisance, adding an extra hour or two to journeys. But for airlines it imposes real costs.  Qatar Airways posted a 766 million dollar  profit in the 2017 financial year.  In the 2018 financial year, it lost 69 Million dollars. Operating costs were up by 15%; passenger numbers were down 9%. “We didn’t raise the ticket price,” says Akbar al-Baker, the CEO. “We had to absorb the additional cost.”
Emirates and Etihad, the flag carrier of Abu Dhabi, run five daily flights to Beirut. With the detour around Syria, they log an extra 2.7m km every year. Depending on the aircraft, that means up to 19 million litres of additional jet fuel, about $11.4 million at current prices. {formatting changes by me to make this fit}

@DavidRicherby points out, fairly, that this local problem is a bit different from the great circle route's need to make an adjustment, in terms of how much extra time and effort a given regional route costs, but it's useful as an illustration of how costs go up when these problems have to be dealt with.
I don't want to have to worry about ...
Then don't.  What you worry about is under your control.

How many airplanes has Qatar airways lost in the last seven years (the length of the Syria civil war) to being shot down? Zero.
What does that say for your odds of this being a low probability
risk?
If you still worry, have you investigated one-flight life insurance?  I used to always buy that whenever I flew, through American Express, back in the 80's and 90's since I was just married and I had young kids.  I'd buy a million dollars worth for about 14 dollars each way.  If you are that worried, buy the life insurance.  It's about the same odds a winning the Lotto for your family.

Full disclosure: I do not now work, nor have I ever worked, for Qatar Airways.

Okay, so what should I do here? Do I take my flight or cancel my trip?

@JoeC That's your decision to make.  How often do airliners get shot down?  Compare that with how many airliners take off and land every day.  What odds are you comfortable with?  Who bought your ticket? You, or your company?

True, I don't know why they are putting passengers at risk like that. Look what happened to Malaysian Airlines back in 2014.

@JoeC Right, that happened once in how many years.  In how many times airplanes flew over that part of the world?  Only you can decide what your risk profile is.

Damn man, this kind of ruined my mood. I was pumped about my trip. Now I'm worried about a missile hitting my plane.

You worrying about a missile is on you; the odds are in your favor.  I'd be more worried about the aircraft having a malfunction, or the pilots making a mistake (see Lion Air, or Air France 447); in the past 20 years, the number of fatal accidents from all other causes, as compared to airliners being shot down by missiles, is orders of magnitude larger for the former.

be honest, do you think its a big risk if I go? Do you think they fly over dangerous zones or anything? On flightradar it tlooks like its the North east of syria.

@Joe Where do you takeoff, and where do you land?

Philly to Doha, then from Doha to Bangkok

@JoeC  The odds are in your favor.  Have a cocktail, or a few, and enjoy your flight.  If you are still worried, buy that flight insurance.

Okay cool, I'd imagine if it was that dangerous Qatar wouldn't put their reputation on the line right?

While I agree that it is probably not a relevant risk to worry about, I do wonder about the advice to buy life insurance. What on earth is that going to help? It's not as if you can use the insurance payout to become any less dead if something does happen.

This is a good answer, but it would probably also help to mention Qatar's diplomatic troubles in the region greatly limiting the countries they can overfly. They don't have as much choice as Etihad or Emirates, due to being banned from Saudi, Egyptian, and UAE airspace.

@HenningMakholm If you follow the comment trail and the question, there appears to be a worry about being shot down or being in a crash.  One way to reduce that worry is what I did with life insurance years ago: if it crashes, what about the ones I care about?   Insurance is a way to buy or rent "peace of mind" regarding catastrophic events and their consequences.

@reirab thank you, I folded that in.

I think you're overstating the cost of avoiding Syria and Iraq on the Philadelphia-Doha route. Syria is trivial to avoid, as the great circle only just clips the country; according to GCMap, avoiding Iraq too would only add about 55 miles to the 6800-mile journey, which is less than 1%. That's not at all comparable with short-haul flights that essentially like to cross from one side of Syria/Iraq to the other but, instead have to go all the way around.

@DavidRicherby I inserted the local problem to illustrate a different facet of the problem, since that was an analysis on the fact that costs increase when an airline can't optimize a route.  I agree with your point, quite frankly, but sometimes one has to use an extreme example to make a point when one is dealing with those who really don't understand aviation beyond " I get on a plane and I arrive somewhere else."  So I did.

Qatar is currently having a diplomatic conflict with Saudi Arabia, Egypt and the UAE. These countries have broken off diplomatic relations.
Their only overt ally in the Gulf is Iran with Turkey and Russia also being sympathetic to them. The rest of the Gulf states are not so willing to go against the Saudis. Not sure where Iraq and Syria stands.


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Is there an equation for jet engine efficiency as a function of turbine inlet temperature?
I know that there is a relation between the turbine inlet temperature and the engine's efficiency. But, can anyone provide an equation or efficiency as a function of just the turbine inlet temperature?
I am looking for something like this: If the turbine inlet temperature goes up by 200K, efficiency goes up by 10%. Any numbers like this are appreciated.
Also, let's say that if GE invents a material that does not melt at all(just imagine), what is the highest temperature that can be produced by burning the fuel assuming nothing can melt.

This answer by Peter Kämpf should explain it. If you are asking about something else, please clarify.

The jet engine efficiency is unfortunately more complicated than just a one-to-one function between static Turbine Inlet Temperature and efficiency. Thermodynamic efficiency of a turbine engine is defined as the useful generated power extracted from the chemical energy added by the fuel.
The following is extracted from a paper format uni book on aircraft gas turbines.

Station 0 is for the engine inlet, the other station numbers are:

Compressor inlet.
Combustion chamber inlet.
Turbine inlet.
Turbine outlet.
Engine exhaust.

Energy IN
The heat flow $\dot{Q}$ added to the engine is:
$$ \dot{Q} = \dot{m} \cdot c_{pg} \cdot (T_{3t} - T_{2t}) \tag{1}$$
With $\dot{m}$ = mass flow through engine, $c_{pg}$ = gas constant, $T_{3t}$ = total temperature at turbine inlet. Total temperature is the temperature reached when a gas flow is compressed isentropically, measured in the stagnation point, and defined as $$T_t = T + v^2/(2 * C_p) \tag{2}$$
So energy IN is a function of:

Static Turbine Inlet Temperature
total mass flow
gas flow velocity at the turbine inlet.

Useful power OUT
The power delivered by the gas generator is:
$$P_{gg} = \dot{}m \cdot c_{pg} \cdot T_{4t} \left[ 1 - {\left(\frac{p_0}{p_{4t}} \right)}^{\frac{\kappa_g - 1}{\kappa_g}} \right] \tag{3}$$
with

$T_{4t}$ = stagnation temperature at  the turbine outlet.
$p_0$ = static pressure at engine inlet, a function of air density and airspeed.
$p_{4t}$ = stagnation pressure at the turbine outlet, which depends on how much energy the turbine has extracted from the gas flow.

Efficiency
If we could vary the $T_{3t}$ only and keep the other variables constant, we could indeed get to the sort of function sought after - but we cannot. Increasing T.I.T creates more thrust, accelerates the aircraft, increases inlet pressure, increases turbine outlet pressure etc.
From Gas Turbine Theory by Saravanamuttoo/Rogers/Cohen, page 81:

The large number of variables involved make it impracticable to derive algebraic expressions for the specific output and efficiency of real cycles.


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What types of antennas are used in a Piper Seneca PA34-200?
What types of antenna are used in the Piper Seneca PA34-200 and where are they are located? The manual is not giving the specific answer to the question. Also, what is the frequency range of the antennas?

You may not be looking in the correct manual.  For Cessna for comparison, there is the POH, the parts manual, a seperate engine manual, and a seperate electronics manual.

Welcome to aviation.SE! We have a generic question on light aircraft antennas already that might be helpful, although it doesn't give specific details of the PA34. And this question has some information about frequencies, but the details (e.g. frequency spacing) may be different in different parts of the world.

Unless you get the plane right from the factory, the manual won’t help much. This post answers the question. https://aviation.stackexchange.com/questions/44305/how-many-antennae-are-there-on-a-typical-small-aircraft-and-how-are-they-connec/44330#44330

Are you trying to get a full list of every antenna on the plane and its frequency? What use would such a list be?

There can be quite a few antennas:

VHF Comm
VOR
Localizer
Glide slope
DME
ADF
Transponder
Marker beacon
GPS
ELT with integral GPS receiver
ELT
FM Receiver

You can search for antenna at a site like chiefaircraft.com to see what they look like and the frequencies they are designed for. Or go to a manufacturer website, like COMANT Industries, for the same.
Some may have multiple functions in one antenna.
Typical locations:

Top of fuselage/wing, (VHF comm, GPS)
bottom of fuselage (belly), (transponder, marker beacon, VHF comm)
top of tail, (VOR, glide slope)

If it is an older aircraft, you might have a Loran antenna as well. This post https://www.touringmachine.com/Articles/communication/2720/ has some common ones.


text:
Which CFD software is used in Boeing and Airbus?
Which Computational Fluid Dynamics (CFD) software is used in Boeing and Airbus, and in the aircraft industry generally?

Please tell those of us not so knowledgeable what CFD stands for.

All of them… In such big companies, you will find that each group chooses its favorite tool, sometimes few tools

@hdrz,open foam?

@IQ240 Probably openFOAM as well. With the right pre- and post- processors you can use any solver

Airbus develops its own CFD software, developed in cooperation with national aerodynamics laboratories like ONERA and DLR.
Boeing does something similar:

Boeing Commercial Airplanes has leveraged academia- and NASA-developed CFD technology, some developed under contract by Boeing Commercial Airplanes, into engineering tools used in new airplane development.

,So they dont use comercial softwears..i didnt know that

Boeing and Airbus started using CFD software before commercial solutions existed, so they basically had to develop their own. Something similar happened with CAD: Dassault developed CATIA, and ended up making it available commercially.


text:
What's the optimal cruise lift to drag ratio of the Piaggio Avanti?
I'm interested in the maximum L/D this plane can achieve. I can't find the necessary data to do the calculation myself.
If I knew the "long range cruise" engine power and assumed 85% propulsive efficiency I'd get pretty close to the real number, correct?
Is the optimal L/D achieved at the so-called "long range cruise" speed? According to Wikipedia this speed is 589 km/h (366 mph, 318 kn). Is this number correct?

Don't know the numbers but I remember from an article by Peter Garrison in FLYING magazine some years back that the Avanti maintains laminar flow on the fuselage to well aft of the cockpit, one of the secrets to its performance.

L/D(max) is achieved at the best glide airspeed, which is certain to be well below cruise speed and even below V_y. I don't know what best glide is for the Avanti, but that's the number you're looking for.

A study of cruise missiles is in order.  Setting max L/D parameter at cruise speed will result in tiny looking wings, with slats and flaps added for lower speed activities such as takeoff and landing.  Aircraft with a wide weight range,  such as cargo or larger airliner, must build in more wing for safety margin.  Cruise thrust should answer your question.  Keep in mind optimal cruising is drag (thrust, really fuel consumption) per distance (helped greatly by sufficient power to go high).

According to some flashcards posted on a random Internet site by an unknown user (i.e., not an official source), the Piaggio Avanti's glide ratio (which is equivalent to maximum L/D ratio) is 2.3 nm / 1000' or about 14:1. It can be expected to achieve that at around 135 knots indicated airspeed. (Give or take: best glide speed isn't actually stated, so I'm applying the useful rule of thumb that it's usually around halfway between best angle of climb and best rate of climb airspeeds.)
Maybe someone with access to a P-180 AFM/POH can chime in with the official numbers.


text:
How does an accessory drive hydraulic system power a crop duster pump?
Aerial agricultural spraying uses pumps, which are usually powered electrically from the starter/generator. Now I have read, that these pumps can also be powered by an accessory drive hydraulic system. How does that work?

I’m not clear on the level of detail you are looking for in an answer.  At the simplest level an output shaft from the engine that could drive any accessory, (like a generator) would be used instead to power a hydraulic pump.  Are you familiar with how hydraulic systems work?  If your question was a bit more specific you might get some answers...


text:
How much does an airliner cabin elongate at altitude?
How much (about) is a commercial plane's cabin elongated at cruising altitude, due to interior-exterior pressure difference?
Of course there should be a slight shrinkage because of temp difference, but I estimate that overall a 30m cabin  should be elongated by few centimeters.

Concorde excluded?

We can identify three effects that have an effect on cabin length:

Stretching due to the bulkhead pulling on the end of the fuselage;
Shortening due to the fuselage expanding in diameter (Poisson effect)
Shrinkage due to temperature

These are simple solid mechanics problems. Given an airplane with length $l$, diameter $d$, wall thickness $t$ made with a material with Young's modulus $E$ and Poisson ratio $\nu$ and linear expansion coefficient $\alpha$ pressurised to a pressure differential $p$, cooled to a temperature differential $\Delta T$....
$$\Delta L = \dfrac{d p L}{ 4 t E} - \dfrac{\nu d p L}{2 t E} - \alpha \Delta T l$$
$$\Delta L = \dfrac{d p L(1-2\nu)}{ 4 t E} - \alpha \Delta T l$$
Let's have a wall thickness of 3mm, diameter of 4m, length of 40m subjected to 0.5bar and 70°C temperature difference. Aluminium $E=$70GPa, $\nu=0.33$, $\alpha=25\mu m/m°C$. Filling in the numbers, we obtain $$\Delta L=3.2mm-70mm\approx-67mm$$
So thermal expansion definitely has the upper hand here, shrinking the fuselage by a few centimetres in total, whereas pressurising the fuselage can only expand it by a few millimetres. The numbers here are very much approximate but the order of magnitude will not change much with "real" numbers.

I wonder if someone did actually made a measurement. It's very easy using a laser meter.

I'm not sure airline operators will appreciate it if you shine a laser through a cabin full of passengers.

Interesting... I'll love to know what's the Poisson's effect contribution...

@xxavier To cover that exact question I already wrote the equation to easily show the Poisson effect, namely, the $(1-2\nu)$. So we have about 10mm extension minus about 7mm Poisson contraction.

Since the elongation of the cabin due to the pressure difference is so small, I wonder how this miniscule difference can cause metal fatigue to the airframe. The length change due to temp difference that is much more impotant, is inherent to the metal, it should not provoke metal fatique. Am I wrong?

I realize the math is the math, but 67 mm seems like an awful lot.  You generally don't see tension regulators in the elevator and rudder cable runs, only in the wings to accommodate wing flex, and that much change in length would play havoc with cable tensions.

Do planes cruising at 10,000m use control cables?

Aluminium has a very different fatigue behaviour than steel: it will show fatigue at any amount of stress, unlike steel which is "safe" from fatigue below a certain amount of stress. And yes, a B737 for example has mechanical linkages to the control surfaces, with hydraulic augmentation much like power steering in a car.

@JohnK Related: https://aviation.stackexchange.com/questions/46179/ I'm would think there is some mechanism in the rudder too to take up slack. Alternatively, the cables get cold too? I agree that 7cm is a lot, but I think the math checks out.


text:
What is the exact purpose of the string attached between front fuselage & the tail section of the transport aircraft's?
]2 228]3]3
Usually I got to notice a string attached between front fuselage to rear tail section of the transport aircraft's, what exactly might be the purpose or function of it? But comparatively, I don't find to see on commercial aircraft like Boeing 747, 737, A380 etc. why is that so!

Also Why did some Caravelles have a very long dorsal fin? (about HF antennas in particular)

If you see one of these on an old Piper or Cessna it is an automatic direction finder (ADF) antenna.

@JScarry: The ADF principle is to rotate the antenna to find the direction of the beacon. How can a fixed antenna do that?

@mins “All ADF systems have loop and sense antennas. With the older ADFs, they are two separate antennas. The loop antenna is a flat antenna usually located on the bottom of the aircraft, while the sense antenna is a long wire that often runs from top of the tail to the top of the of the cabin. (On larger aircraft, the sense antenna may be located on the bottom of the aircraft.)” https://www.avweb.com/news/avionics/183233-1.html

@JScarry: The directional antenna (loop or wire) must rotate per principle to find the null. The sense antenna to remove the ambiguity between two possible directions must be omnidirectional (hence usually it is vertical). See more. So I don't see how the directional long wire could automatically find the direction, unless the aircraft makes turn in the sky. This looks like more a communication antenna, and if you look carefully you will see there are actually two separate antennas.

@mins I”m not commenting on the photo. Just pointing out that on old GA aircraft, like my 1968 Piper, they had a sense antenna running from the top ot the vertical stabilizer to the front of the fuselage. The loop antenna was on the bottom of the plane. My 1963 Cessna has the two antennas combined into one. At one point I could actually sort of fly an ADF approach, and even though it may have looked like I was rotating the plane to rotate the antenna, it wasn’t necessary—just turn the dial to set the course and adjust your track for the wind.

@JScarry: Got it! Here is what you mean. So in this system, the sense antenna was definitely not omnidirectional, but as it's only to remove the ambiguity, it was obviously sufficient. I must apologize for my previous insistence.

That is an end-fed long wire antenna for HF radio use.

+1, but there are actually two antennas (see the insulators at the tail end), used by two HF transceivers.

I missed the second one. why two wires?

An antenna can be used for reception while the other is used for transmission. That's what military call "Simultaneous Operations" (SIMOP). See this paper. Too bad the question was closed as this is a particularity of military aircraft not covered in the other linked question.


text:
Does the X-59 comply with the "area rule"?
The Lockheed Martin X-59 was rolled out yesterday :-)

Brett Tingley, Watch NASA's sci-fi-looking X-59 'quiet' supersonic jet roll out of the hangar, August 2023.

I am no expert here (and no English native), but to me, I can see the shape more or less according to "area rule" until the engine intake comes up and the wing "is still there".
Does it make any sense? Does the "area rule" not matter after (e.g.) 70% of the aircraft length axis? Does the fact that it is an air intake change the "area rule" effect (i.e. it's sucking air in)?
Also, I see a lot of riveting on the fuselage, I would be expecting a lot "cleaner" surface at the front (check "green area" under cockpit). Maybe it's just because it's a prototype?
Thanks in advance! This is my first question at this site ever! I have been following this forum for long and it's my favorite :-)

Welcome to Av.SE - nice first question, about a wild-looking machine!

Well the engine starts where the wing becomes thinner and thinner so it might be that some area rules is anyway preserved at least until there. Anyway the main purpose of the X-59 is to reduced the sonic boom, not the drag

One of the weird things about area ruling -- the area that goes 'through' the engine does not count towards your area.  So although the engine looks like a large increase in area, it isn't from the fluid's point of view.
In most simple terms, the wave drag is caused by pushing the air out of the way -- the air that goes through the engine does not get pushed out of the way.
As mentioned other places, the X-59 is designed to minimize the sonic boom -- not to minimize the drag.  It can't have a horrible area distribution for drag (otherwise the thrust requirement would get prohibitive), but the area distribution is optimal for boom.  Fortunately, these shapes are somewhat correlated -- strong shocks that cause lots of drag also cause loud boom.  So while there is a drag/noise tradeoff, they aren't entirely opposed metrics.

Thanks a lot. So my feeling on the air intake not counting for the area rule was on the right direction :-)
After some more googling I read that wing mounted jet engines do not account for the area rule but they do if they are on the fuselage... I would appreciate any link where I can learn a bit more about the topic :-)

I don't have my hands on a good reference for this, but the way you typically model engines (body or wing mounted) in a wave drag code is to take the inlet shape and extend it far in front of the aircraft.  Then you take the outlet shape and extend it far aft of the aircraft.  When you take cross sections, the first and last cross sections will have non-zero area (they will have the capture and exhaust area, respectively).  You can then subtract out the inlet area and handle the exhaust area in a number of ways (it doesn't really matter how).

The wave drag calculation actually uses the 2nd derivative of the area distribution, so an offset or linear function added to the area won't matter.  So you extend the inlet and exhaust tubes to infinity, take the cross section areas, subtract them out, take the second derivatives, and go from there.


text:
What is the dark spot visible below the cockpit on A-10s?
On most A-10s I have seen, the area under the cockpit is darker than the rest of the plane. Is there a reason for this?

Does it have anything to do with the cylindrical device extending down on a vane also painted the same color? I'll throw in a WAG that the cylindrical device is a camera or other sensing device, and that the color has to do with aiding whatever that device does?

@Terry, no, they're not related. That's a Pave Penny laser spot tracker, which allows the use of precision guided munitions.

I'm more concerned with the fact that the circular area around it is much lighter than the rest of the plane... ;-)

It's a false cockpit, a type of camouflage patented in 1980 by Keith Ferris, a US artist and camouflage designer. From some angles, it makes it difficult to determine the orientation of the aircraft. The Canadians were the first to apply it; pictured is a CF-18 Hornet with one:

Notice how at a glance, it takes a second to realize the Hornet is inverted and pulling towards the ground. During dogfights this can be enough to make opposing pilots think the aircraft is going a different direction. It might not seem like much in a photo, or if you're watching an aircraft fly past at an air show or airport. In the stress of combat while pulling extra Gs it's more than enough to confuse or delay a reaction.
For the air to ground mission, this is particularly important. If an A-10 encountered antiaircraft fire or an enemy aircraft it would have to rely on its own agility to escape or gain the upper hand. Other nations have adopted this technique — I've seen French and Russian types, and possibly Gripens of some air force. As far as I know, the A-10 is the only US aircraft regularly camouflaged in this way.

didn't even have to read it, that picture said it all, thanks :) Very cool

Interesting. I'm surprised that USAF and USN haven't adopted this more generally.

The USN also implemented it on their F/A-18s for a while. AFAIK it wasn't adopted in part for cost reasons, it's cheaper to just spray the entire aircraft in a single colour... Ferris advocated a lot more, including spraying the aircraft in geometric patterns in many shades to break up its outline. Worked well, but was too cumbersome and expensive for large scale adoption. The Canadians have far fewer aircraft, so total cost of adoption is quite a bit lower than it'd be for the US.

You would think the cost of paint would be far less than even the slightest risk of losing a plane and a trained pilot.

Given that the last aerial dogfight was in about 1986 and even that was in the film/fiasco Top Gun it's all probably a bit moot.

@davey : don't forget that there wasn't a single air battle between fighters ever since, as there wasn't any war in the last few decades between countries which could both field fighters, so there was no opportunity to any fight, either distant or dogfight.

@davey There were plenty of dogfights in the 1991 Gulf War, according to Wikipedia; there were also air-to-air kills in the Kosovo conflict.

@jwenting "Ferris advocated a lot more, including spraying the aircraft in geometric patterns in many shades to break up its outline." That sounds a lot like the dazzle camouflage used by the British and other navies during WWI and a little later.

@DavidRicherby yes, they're quite similar in many ways.

"Notice how at a glance, it takes a second to realize the Hornet is inverted and pulling towards the ground." And perhaps even more scary... imagine it comes up on you from above and behind... and looks like it's diving inverted into your flight path.

how ingenious !

Also used by the South African Air Force on its Gripen fighter aircraft and, before that, its Cheetah (upgraded Mirage) fighter aircraft.
The intention is to create momentary uncertainty as to which direction an aircraft may turn, both for air-to-air encounters against other aircraft and when doing low-level manoeuvring in the ground-attack role.
An image of a South African Air Force Gripen C, showing the false cockpit on the bottom:

By Brent Best
And an image of a South African Air Force Cheetah C showing the same:

By Christo Crous
Note the diamond-shape on the bottom of the Cheetah C. A similar pattern is painted on the top surface of the SA Air Force's Gripens. This reportedly helps create more uncertainty when seen in  brief glimpses during combat, similar to the way dazzle camouflage on ships in WWI worked.
This is an illustration, taken from a flight sim, of what the effect looks like on a Cheetah C with a mostly 'clean' configuration (no drop tanks or bombs):

South African Air Force fighter aircraft have used the false cockpit and diamond-shape camouflage ideas since the last 1980s, after proving the concepts through testing.

looks like metal fatigue, dirt, grime, and age actually improve the effect

It can make a difference, which helps because in combat aircraft don't remain pristine for long.

Ah, I was apparently thinking of SAAF Gripens, then! I'm not sure what's up with the dark diamond on top surfaces, but it does seem to add to the illusion.

The Hungarian Air Force has since adopted it on their Gripens and Saab painted one on the underside of its Gripen NG demo aircraft, so it may yet be used by the Swedish Air Force too. Rumour has it that they were impressed by how well it worked for SAAF Gripens during Exercise Lion Effort 2012 in Sweden, where the SAAF pilots achieved high kill ratios in close-in air-to-air combat.
The purpose of the diamond is to cause just that extra bit of confusion for the opposing pilot, as it creates conflicting shapes. It was painted on both top and bottom on the Cheetahs, only the top on the Gripens.

Wikipedia cites the biological concept of automimicry, or intraspecific mimicry, where a species develops a part of the body which appears similar to another part, e.g. a tail appearing like a head, so that predators become confused as to the orientation or direction of movement of their prey.
As per egid's answer, this technological form of automimicry ideally helps to degrade an enemy's capability to successfully attack an A-10C (or similarly painted aircraft or vehicle).
See also the similar concept of dazzle camouflage or razzle dazzle used on combat and merchant naval ships during World War I.

Dazzle Camouflage is super-cool, eg http://blog.iso50.com/wp-content/uploads/2013/01/dazzle-camo-2-450x184.jpeg

There was an article on this in Aerospace magazine way back in the late 1980s (I still have a photocopy somewhere).
They called it Visual Stealth. The article included the long history, including
using lights to illuminate the darker regions of aircraft when viewed from the ground.
One picture I saw clearly showed a 'tail shadow' painted on the bottom
of an F16. False cockpits were common, as were painting the tops and bottoms
different colors. Ground Strike aircraft would commonly have yellows and
brown camouflage, white in the winter (Germany). The Navy was using blues and
grays, with the tail squadron markings rather dull.

The Smithsonian Air & Space Magazine website also had a short feature on visual stealth in 2013 called How To Hide an Airplane. I imagine it's probably less detailed than a trade publication, but they have some pretty awesome pictures including this one -- There are two aircraft in that shot.

@voretaq7 huh, I remember seeing that article but I must have never actually read it

Painting top and bottom different was done because aircraft would then stand out less when normal way up. Mostly of interest for low flying aircraft, which is why it's mostly gone now, as the proliferation of MANPADS has caused operations to move a lot higher than they were at the time (when longer range SAMs and AAA were the major threat).

"Visual stealth"? Isn't this just camouflage? :)

I think it's "clever camouflage" @egid .   Camouflage is where the plane is coloured the same as the background.   Visual Stealth is where clever misrepresentations of its own structure are painted on it (like butterflies have eyes on their wings, by the way).

authors: Bob Jarvis - Слава Україні

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Has there ever been a case where elephants are carried by aircraft?
I know that today's aircraft can carry very large amounts of cargo, and some (presumably military heavy transport aircraft) can even carry tanks.
However, I've been thinking, has there ever been an occasion where live, adult (mature) elephants are transported by aircraft?
In terms of weight, most elephants don't exceed the maximum weight of large cargo aircraft. But has there really been an air transport of elephants in aviation history?
Would that even be possible? Wouldn't a grumpy elephant (and they most likely will be grumpy for being squeezed into a tight cargo hold) cause the aircraft to crash?
I mean, the slightest movement of an elephant that weighs more than 3 tons would most likely cause the aircraft to roll, pitch, or drop, and may even break the fuselage if the elephant's force is great enough.
So, my question is, has there been such an occasion? And if there isn't, is this even possible?
Thanks for any insights on this!

It seems highly unlikely that an elephant would just be shoved into a wide-open cargo hold and allowed to roam freely during flight. The obvious move is to put it into a crate that’s just big enough, and then fix that crate in place after loading (like any other large/heavy load) so it can’t move around enough to cause problems during flight.

@nobody I know that, and I apologize for any misunderstanding or confusion of me asking if they are put into the aircraft cargo hold without any restraints. It's just that I originally though they may bring down an aircraft even if the elephant is inside a crate and secured. Do you suggest any edits that can convey my question more clearly for future viewers? Thanks in advance!

There have been things more complex than that transported in cargo holds, including whale sharks, in their tank. See for instance https://www.youtube.com/watch?v=uveltPY1LHk

@jcaron That's easy, you just need a tank made of transparent aluminum. (And a transporter.)

I recall a Texas Billionaire moving an entire herd of elephants from Africa to Texas, either in the late eighties or early nineties, for his personal perusal.  Don't recall the man's name, but I remember it was filmed either on 60 Minutes or 20/20.

@JohnHunt: Doesn't necessarily mean they were moved by air; Africa to Texas could easily be done by ship.

@Vikki This is begging the question (the elephant in the room! ) of why they are doing it by plane, considering how expensive it is. Look at WPNSGuy's answer: from Puerto Rico to Jacksonville seems very doable, as there are no long parts on land (unlike the transfer from Islamabad) and the climate must be good (unlike the one from Anchorage). I suppose the elephant would suffer too much if kept inside a tight cage for too long. A ship could go from Puerto Rico to Jacksonville in 2-3 days. If that's too long, I wonder how long an elephant can resist.

Transporting an elephant is not a problem. Its called sedation/tranquilizer.

I know for a fact that black rhinos were, at least historically, regularly airlifted (upside down no less) by comparatively small helicopters with some regularity as part of relocating them for conservation efforts. I would actually be a bit amazed if something similar has never been done with an elephant (a S-64 or an Mi-10 could easily handle even the biggest ones if they were sedated).

PS elephants weight from 2000 - 6000 kg so there's quite a variation.  (Height 10-13 feet.)

@Vicki;  The animals were shown being unloaded from a modified cargo plane. Wish I could recall the specifics.

@FabiosaysReinstateMonica; The purpose given for the Texas event was the billionaire's desire to protect the species. I'm sure it had nothing to do with his ego.

Pakistan to Cambodia. DHL.
https://www.stattimes.com/news/dhl-safely-relocates-the-worlds-loneliest-elephant-air-cargo/?infinitescroll=1

the first adult elephant to board an airplane in Pakistan

Puerto Rico to Jacksonville FL. Atlas Air 747. https://www.jacksonville.com/picture-gallery/news/2023/05/12/puerto-rican-zoo-animals-flown-jacksonville-way-new-homes/11858127002/

a cargo of one elephant, one rhinoceros, a hippopotamus, a donkey and an impala

Elmendorf AFB, AK to San Andreas, CA. USAF C-17. https://www.af.mil/News/Article-Display/Article/125251/pachyderm-pcs-elephant-finds-new-home-courtesy-of-air-force/

"We contacted local authorities in Anchorage and began the lengthy process of requesting an Air Force flight for Maggie," said Pat Derby, PAWS co-founder and president, who agreed to reimburse the Air Force. "After several weeks of negotiating, we secured permission from the Air Force to fly Maggie for a price -- between \$215,000 and \$300,000."

Thanks, this is exactly what I'm looking for. Your answer is very informative and helpful. Again, thanks for the great answer!

And that wasn't a full list just the first few I came across. There have been others.

Really? So elephants can really be transported inside aircraft rather easily.

Well, not "easily". Specialized crate, lots of training, lots of money. But is IS done.

I do have a question though: are they tranquilized, or are they just secured inside a large crate and loaded into the aircraft?

An elephant beverage cart can be developed.

@AircraftEnthusiast007 Maggie is awake during the flight

I thought they had flown elephants on C-46s over the Burma hump in WWII, but it looks like the elephants walked to China. They did, however, fly 3000 mules. "The airlift brought about 3,000 mules over the Hump, mostly for the Chinese army. They rode four mules to a transport, with four Chinese “cowboys” keeping them under control. Crew members said it took a day to clear the smell out of the airplanes." https://www.airandspaceforces.com/article/1009hump/

fantastic answer @WPNSGuy .  elephants weigh from 2000 - 6000 kg so there's quite a variation, i wonder if any weights available from the known cases.  6k is much different from 2k i guess.

If I'm not mistaken TANKS weigh 20-50 ton and they regularly go in air transport .. is that right?  (I appreciate the issue is the object wiggling around.)

Apparently the abrams tank (the "usual" current US tank) is 65t and it can go by C17. Sounds like you could take 10 or 20 elephants !!

@Fattie - Weightwise, a C-17 could take a dozen or so elephants. Not so sure about spacewise, once you include the crates they ride in.

Operation Dumbo Drop. USAF C-130. U.S. Air Force Press Release
Nah Trong, Vietnam to Chu Lai
April 1, 1968
2 Elephants, one at a time, were flown on a C-130 from Nah Trong, Vietnam to Chu Lai to help villagers move trees. They were sedated during the trip so they wouldn't move. They were then moved from Chu Lai to the village with a CH-53 helicopter.

DIRECTORATE OF INFORMATION, Headquarters Seventh Air Force TAN SON
NHUT AIR BASE REPUBLIC OF VIETNAM APO San Francisco 96307
FOR IMMEDIATE RELEASE 4-68-40
AIR FORCE FLIES ELEPHANT AIRLIFT
NHA TRANG (AF)
Air Force C-130 Hercules transport crews are used to flying
almost anything you can name. Even elephants. Flying elephants isn't
easy. It takes the help of the U.S. Arny Special Forces, the Marine
Corps, the United States Agency for International Development (USAID),
the Cleveland Zoo and the U. S. Bureau of Narcotics. It all began when
an Army Special Forces team at the diminutive Vietnamese village of
Tra Bong offered to help the 400 Montagnard and Vietnamese families in
the area start their own industry. With the heavy growths of timber in
the area, a sawmill looked like the answer to the villagers' economic
problems, and with the help of USAID, the villagers soon had a
burgeoning business going. Before long, however, the villagers had cut
down all the trees near enough to the sawmill to haul by hand, and a
problem arose. The local terrain was so rugged that machinery for
hauling logs was useless. Tra Bong was in danger of losing its only
industry, Elephants, the villagers said, were the only answer. Two
suitable elephants were found and with the help of USAID funds,
purchased at a price of 70,000 piastors (about $590) each.
Unfortunately, however, the elephants were located in Ban Don, more
than 170 miles from Tre Bang. The pachyderms couldn't be transported
by land because the trip was too long and the Viet Cong controlled too
much of the intervening territory. A move by sea was ruled out because
it would also take too long and there was the danger of the elephants
becoming seasick. The only way to move the 3-ton, 6-foot-high animals,
it appeared, was by air.
Special Forces Captain Scott Gantt, the man given the job of moving
the elephants, decided to call on the Air Force. When Gantt approached
7th Air Force with his project, he was told that the elephants could
easily be moved in the cavernous C-130 Hercules cargo transports,
provided the animals could be immobilized enough to prevent their
thrashing around in the aircraft.
After hours of transoceanic phone calls, Gantt finally learned from
the Cleveland Zoo that a drug called M-99, manufactured by an English
firm, would keep his 6,000-pound charges docile for the necessary
time. When Cantt arranged for a shipment of M-99, however, he ran
afoul of the U. S. Bureau of Narcotics, which demanded that he spell
out how the drug was to be used before it could be shipped.
Gantt complied, the drug arrived, and on April 1 a C-130 crew from
Task Force Bravo, a special airlift mission based at Nha Trang Air
Base, landed their aircraft on a dirt strip near the Special Forces
camp of Trang Phuc and prepared to take on board their most unusual
passengers ever. While the first of the animals stood on a cargo net,
Gantt Stood behind him and fired a hypodermic dart from an air gun
into the elephant's rump, injecting him with the K-99. Five minutes
later, "Clyde," as the Green Berets had nicknamed him, lay dosing
peacefully in the net. A forklift hoisted him onto a wooden platform
and lifted him into the gaping rear doors of the waiting C-130.
With Clyde strapped firmly in place, the Hercules crew took off for
the Marine Air Base at Chu Lai, 20 miles from Tra Bong. At Chu Lai,
Clyde was removed from the C-130 and still wrapped in the cargo net on
his platform, was slung beneath a Marine CH-53 "Super Jolly Green
Giant" for the final miles of his trip. The chopper whirled away in a
blast of sand and dust, and 15 minutes later Clyde was settling to the
ground at Tra Bong in front of the watchful eyes of more than 2,000
villagers. Then, after a repeat of the first trip with Clyde's
partner, the village and the sawmill were back in the lumber business.

I'm absolutely gobsmacked to discover that the movie was really based on a true story!

I wonder if the people who named the operation had watched the Disney movie Dumbo when they were kids. This operation is an interesting one, and the name almost certainly has some kind of reference to the Disney movie.

Dumbo was released in 1941, the mission was in the 70s, so it's certainly conceivable that some of the people involved had been kids when the film came out, and many of the older folks probably had kids who were the right age to go see it. Anyway, by the 70s, Dumbo was deeply ingrained in the cultural mind. If you're planning a mission that's going to make an elephant fly, the name writes itself.

Back in 2016, a 747 flew a total of 17 elephants from Swaziland to zoos in Texas, Kansas, and Nebraska

The plane, which brought 17 elephants from Swaziland and dropped five off in Dallas early Friday morning, arrived at Wichita Eisenhower National Airport at 12:31 p.m. Friday with its controversial cargo. The final six elephants are destined for the Henry Doorly Zoo in Omaha.

The large crates containing the elephants were tightly enclosed, with narrow slits providing ventilation but not much of a view for the crowd gathered outside the fence. That didn’t dim the enthusiasm much, though.

Veterinarians aboard the overseas flight reported that the elephants were eating, drinking and, in some cases, sleeping, Dennis Pate, executive director and CEO of Omaha’s Henry Doorly Zoo and Aquarium, said in a statement.
Graham characterized the relocation effort as “part of an ongoing rescue mission to provide safe haven and a more secure future” for the elephants.

Video of unloading elephants from the airplane

Related news articles
https://www.kansas.com/news/local/article65247617.html
https://www.cbsnews.com/texas/news/african-elephants-arrive-on-special-747-bound-for-the-dallas-zoo/

"Eating, drinking,..."   And what else? :)

Cargolux is a cargo-only airline based in, you guessed it, tiny Luxembourg. And in 2012, it flew an elephant that had arrived in Luxembourg by truck to Pittsburgh zoo:

On Tuesday a Cargolux plane takes off from Luxembourg bound for New York with a very special passenger onboard: Thabo-Umasai a five year old elephant born Dresden zoo in Germany will make the trip to his new home in Pittsburgh Zoo as his current German home lacks the space to house him.
The animal will arrive in Luxembourg by truck before flying to the United States. A delicate operation, as Thabo weighs 1.9 tons and measures 2.20 meters.

Cargolux regularly flies special cargo, like racing horses, typically accompanied by veterinarians. The source does not say, but I could imagine Thabo to have been sedated and similarly accompanied during his trip.

Here's a video:

Here's a new story about a pile of elephants on a flight (not much actual video of the cage etc),

It would improve the answer to include some key details like year, air carrier / plane info, departure and arrival airports, name of elephant, etc.  As-is, this is basically a link-only answer, plus maybe the thumbnails, although if the video links rot they'll also die I assume.

quite so @PeterCordes , it's a tricky one since it's a "let me google that" question, although a fun question.  We're a quarter way in to the 21st century.  All you have to do at any point on Earth is speak in to the air "give me all information about elephants on airliners" and you will instantly get every video ever of this happening, and indeed these days, a poorly-written spoken "AI" summary of the dates etc. So I think it's sort of horses for courses, IDK. On a more serious engineering-like question what you say is certainly the case.


text:
Antennas on airliner wings?
From the question about sharp pods under airliner wings, I think the right term is anti-shock bodies, or flap actuators/track fairings.
What's the little antenna looking thing extending off the rear end of it? My best guess it something anti-static? Why are they necessary?

I should add that this is an American Airlines Airbus 321.

You're very right. It's a static discharger or "static wick", and it is used to dissipate the static electricity accumulated during flight. The electrical buildup happens during flight through precipitation, clouds, dust, etc., and is known as "precipitation static".
Once the static reaches a certain point, it will discharge. Without wicks, this happens through antennae and can really mess with communications or navigation. Wicks make sure that process doesn't cause problems.


text:
How can I determine the quality of training provided by a CFI at a local flying club?
I'm considering getting a private pilot license, but considering that it is more dangerous than driving a car (with pilot error being a large factor of that), I want to make sure I train with a CFI and aircraft that are safe, and also ensure that I learn the habits necessary to become a safe pilot.
Are there any objective (or fairly reliable subjective) ways to determine the quality of training provided by CFI at a local flying club?

Jeff, I really appreciate that you ask for safety before asking for the price. Unfortunately it takes some experience and time at a school to say if the equipment and teaching methods are safe or not, but I'll try my best to provide you with some of my insights into flight training.
I personally tend to the bigger flight schools. Having a strict training concept and standardized methods is a huge benefit in safety. If the same teachers also do more advanced training like IR or MEP your PPL training will most probably also be more intense. Your training should concentrate on learning to fly not flying the nicest routes but of course you should also enjoy your time. That's why you should of course also have a look at the people who are there. They should not only be friendly, but also be professional and well organised. The most annoying thing during flight training is bad organization and the changing of schedules due to absolutely avoidable reasons.
Good maintenance is key for safety. Here again, a big flight school that can do it's own maintenance has a lot of advantages. Often it happens that there are minor problems which should be fixed before the next flight without being a big safety hazard. It's better to squawk this and wait ten minutes until maintenance has fixed it, rather then flying without having it fixed, or cancelling the lesson. If the flight school has its own maintenance and they are happy with their work they will tell you and also show you around. Honestly the only thing you can do is to look if the hangar looks clean and tidy. If you decide for a smaller school without its own maintenance, it should at least be done at the same airport. Otherwise this could cause regular delays in your training.
Also think of yourself. During your solos and later when having your license you are allowed to and you will fly alone without an instructor. Be motivated to learn more than you have to. Know your aircraft and ask your questions. RTFM should not be the general answer of your flight school but you should spend some time doing it.
I made a list with all my questions before visiting different flight school so I don't forget to ask them. I would sugest you to do the same before getting there. If you for example ask for some more detailed information how many flight time you have to do with an instructor before flying solo and what exercises and maybe progress checks you'll have to do prior to it, you'll get a good insight how structured the flight training is. Also don't forget to ask about the theoretical part. That's really dependent on your self if you prefer to learn with books or with a teacher in front of you.

All excellent points. I'll add that you should consider taking an intro flight with any school/instructor you're seriously considering. Things to watch for are checklist use (they should be using checklists, and making you do so as well) and teaching style/personality (you're going to spend a lot of time in a small plane with this person - make sure you'll get along reasonably well).

Absolutely! This is more often offered by smaler schools (at least in Europe) but you should ofcause ask, as this is the really best insight you can get.


text:
What happens if Marine One's rotor blades fail?
While I was reading news, I came across this image of Marine One:
This is Sikorsky UH-60 Black Hawk

Citation of Image 1

Citation of Image 2
On a closer look, I see there are two big exhausts just under the blades at the top of Marine One. And there is also a big wing at the end of Marine One.
I know I would be wrong, but I am not sure about it: I thought these two things are inter-related to each other in case of rotor failure, i.e if the rotor fails then the exhaust would pump out air backwards like a blast giving it forward thrust, and the wing at the end would help it in direction or upward/downward thrust balance (just like in F1 racing cars). Essentially making it work like a plane for some time until it lands safely.
I tried searching about it, but could not get information about it. I did come across an older Marine One image whose exhaust is too small and is at the side rather than at the back and this does not have a wing at the back:
This is Sikorsky SH-3 Sea King

Citation of Image 3

Citation of Image 4
I have 3 questions:

Why is the exhaust at the back of new Marine One so big now?
Why is there a wing at the back of the new Marine One ?
What would happen if rotor blades of Marine One fail ?

Citations

Welcome to Aviation.SE! If the rotor blade fails (comes off/breaks), the helicopter will crash. The exhaust nozzles do not provide lift and the tail doesn't either. I think somebody should be able to give you a good answer in detail.

See https://en.wikipedia.org/wiki/United_States_presidential_line_of_succession.

@FredLarson Doing a Ctrl+F, then typing Marine One and hitting Enter does not show any mention of Marine One on the page you mentioned.

@GypsyCosmonaut: You completely missed the point.

@FredLarson meaning? I didn't understand you.

Meaning if the rotor of Marine One fails, the presidential line of succession comes into effect.

Hahahaha.. Okay, got it. But then what is the use of that big exhaust and big wing at the back?

This helicopter is a (slightly modified) black hawk. You can now search what you want about this helicopter and ask questions about specific parts of it (either the regular version or the one for the US president)

@GypsyCosmonaut:  Should it?  Or are you making the mistake of assuming your particular browser's search command (which is what I'm guessing the Ctl-F is supposed to be) is universal?

@ManuH Thanks. But I'm not sure if someone is right now typing an answer to this question or not, if I delete the question and they have typed a long answer then it might be a waste. I would ask specifically if I do not get an answer to this.

You might get some info on the "big wing" here: https://aviation.stackexchange.com/q/25308/520

Can you cite your images?

The two large exhausts just below the rotor pointing back serve the exact same purpose as the ones pointing to the side do on the older helicopter - to exhaust burnt fuel from the twin turbine engines that provide power to spin the rotor shaft. Aiming them backwards vs sideways is simply a design decision made by the manufacturer when balancing out all the other design decisions that needed to be made. While there is some force from the hot exhaust gas, it's negligible in terms of what is necessary to move the bird or keep it flying.

No helicopter can fly if the blades fail.  The overwhelming majority of the lift produced, required to counter gravity, is from the blades. There is some lift from lots of other parts of the helicopter but all combined, nowhere near enough to keep it flying.  The blades are also required to manoeuvre the helicopter.
It is also most probable, and this what usually happens, that if one blade fails, or is lost, the resulting imbalance in the heavy, fast rotating rotor assembly leads to instant breakup of the aircraft.
The wing at the rear is called an horizontal stabiliser and its job is to push the tail up or down, depending on the load and speed of the helicopter, to keep the fuselage more or less level throughout the operating range of the craft.
Marine One would simply plummet if the blades failed.

Okay.. Thank you. My question has gained some negative feedback. How can this question be improved so as to help the community ? Or shall I delete it because this is just another stupid duplicate question.

Neither. I don't know why it's been downvoted and it's not a duplicate.  Quite simply, no-one has asked this "obvious question" before so it belongs here. I am very much of the school there are no stupid questions; perhaps not right time, right place but if this is not a place where someone who does not understand can ask these questions, then where is?  +1 from me to help the natural balance of the interwebs.

Blade failures are one thing that is not trained, discussed or thought about since every helicopter pilot knows, unless they are slow and close to the ground, that they are dead if it happens.  Not nice reading, but this is typical of what happens.  P.S. you really need to edit your question to provide the attribution to the images. We are big on crediting sources here and it's possible some people might downvote because of that.

Finally, I don't see what's wrong but if you want advice, by all means  try asking here

Another +1 on citing image sources.

Full disclosure - the "Not nice reading" link apparently needs access, which I seem to have via my employer, even though I didn't realize I had until I clicked. (Circular logic is circular)

@FreeMan Ah, yes, I  was only reading the summary. I think this accident report is accessible without restriction.

@Simon I did all the citations now. I did not know it was that important in this community. Thanks for helping

Well, on a different question on here, I was informed helicopters could safely land if the engines failed...

@Cloud Engine failure and rotor (or blade) failure is not at all the same thing.

I served as a Helicopter Crew Chief on a Sikorsky H-34 helicopter in Vietnam and I agree that blade failures are incredibly rare on properly maintained aircraft.
On most helicopters the main structure of the blade (spar) is hollow and contains pressurized gas — usually nitrogen. Before each flight, the Crew Chief and Pilot check a gas pressure indicator on each blade. If a crack develops in the blade, the gas will leak out and likely indicate a problem before there is a failure.
Military helicopters are designed to work very hard and handle a great deal of stress. Marine One probably has a very easy life compared to its counterparts in the rest of the world. I’d say it is a very safe aircraft.

To answer the other questions...
Why is the exhaust on the Blackhawk so much larger than the Sea King? One reason is - the Blackhawk has larger engines, 1500hp as opposed to 1200hp. The primary reason, though , is dispersing the exhaust heat, making the Blackhawk a harder target for heat seeking missiles. Note the fairing above and around the exhausts, also part of the heat disperson system.
Why does it have a wing on the back? This Q/A thread suggests it is tied to airspeed, not the cyclic, for stability reasons.
As for a main rotor blade failing... yes,  you're pretty much dead if that happens. One reason helicopters cost so much more per hour to operate than aircraft is the more rigorous maintenance and inspection schedule, especially on the main rotor and blades. Fortunately, main rotor failures outside of the blades hitting something due to pilot error are extremely rare.

(o.O) Ohhh..., heat dispersion..., I see... Nice..

According to Wikipedia, the current generation UH-60L's have two General Electric T700-GE-701C turboshaft engines, producing 1,890 hp each. https://en.wikipedia.org/wiki/Sikorsky_UH-60_Black_Hawk#Specifications_.28UH-60L.29


text:
What is the maximum angle the F-16 can turn in $x$ seconds while flying at corner speed?
How can one calculate the maximum turning angle the F-16 can turn in $x$ seconds flying at corner speed? Does it depend on height or weight?

To calculate this, you need to look at the energy Maneuver diagram for the aircraft. This diagram depicts, for a specified altitude and gross weight, the excess power per unit pound of weight the aircraft would have at full afterburner at any g-Loading and true airspeed. There would be a different chart for each aircraft configuration, gross weight and Density Altitude combination.
Instantaneous Turn rate is depicted on the vertical scale, true airspeed or mach number is depicted on the horizontal scale. The concave curved lines that go from upper left to far right represent flight conditions of constant G-loading, while the straight lines that radiate from the origin represent constant turn radius. The peak of the flight envelope, (at about Mach 0.7, 20 deg/sec turn rate and 8 Gs, is corner velocity. The lines that start at the left boundary or at the bottom, go upwards, curve to the right and then back down again, and are labeled with values 600, 400, 300, 0, -200, etc. are called Ps, (pronounced P-sub-S), lines. They depict the specific power, or actually, specific excess power - a measure of how much power per pound of aircraft weight the aircraft would have left over to climb or accelerate at the depicted point on the diagram.
So at the top of the diagram, at the corner velocity, where the turn rate is near 20 deg/sec, the specific excess power is less than -800. The -800+ Ps curve indicates that the aircraft, if it established flight at those conditions, would be bleeding energy (airspeed or altitude) at a rate in excess of negative 800 ft/sec.
The best performance on the diagram that can be sustained, on the other hand, is the highest point on the zero Ps line, which is at mach 0.8, 7 Gs, and it would produce a sustained turn rate of just over 14 deg/sec.
So, in a level turn, at Mach 0.8, 7 Gs, and 14 deg/sec, the F-16 could turn 180 degrees in about 13 secs.
Of course, if the aircraft performs the turn in a descent, it can make the turn in less time. This is indeed a common training maneuver, to turn 180 degrees in the shortest amount of time possible. It is performed by rolling into 135 degrees of bank at or slightly above corner velocity and pulling at maximum G-load. The maneuver is performed at maximum available G-load, in a constant plane tilted at 45 degrees from the horizontal. Bank angle (starting at 135 degrees), decreases throughout the maneuver, reaching 90 degrees bank after 90 degrees of turn, and 45 degrees bank at the end of the maneuver (after 180 degrees of turn). At 15,000 feet MSL, this will generate almost 20 degrees per second, and can be done in about 10 seconds.

For an uncoordinated turn, all things are possible, consider a hammerhead, wing over, or Lomcovak! For a constant altitude coordinated turn, weight affects the load and stall which does play a part. The two primary factors are bank angle and rate of turn. As the angle of bank increases the load factor or  thrust required for speed will limit the aircraft's ability to bank.

To completely answer your question requires more information such as the weight, load limit, stall speed of the aircraft in the configuration of the turn, atmospheric conditions, etc.
As the angle of bank and turn rate increase, so must the speed and load factor, soon the power available or aircraft structural capability is exceeded. As the aircraft approaches a 90deg bank the vertical lift component approaches zero, the speed and load required to hold altitude approaches infinity.
 The graph and turn performance of the F-16 are discussed in detail here...
The "FAA's Pilot's Handbook of Aeronautical Knowledge" gives the formulas for rate of turn and turning radius on page 4-34. Chapter 15 of "The Science of Flight" by W.N. Hubin (1992) is the source of the other formulas.

The variables used are:
  V = true airspeed in knots
  R = turning radius in feet
  θ = bank angle in degrees
  ω = rate of turn in degrees per second
  g = 11.26

  Note: The FAA formulas use deg/sec, while Hubin uses rad/sec.

For example, at 120 knots and a 30° bank angle, the turn radius and rate of turn are:

Hubin goes into greater detail and provides information for other scenarios.

The formula for a standard rate turn (3deg/sec) is...

but other velocity's can be plugged in.

could you explain to me how to obtain this value g = 11.26 ?
thanks by advance

@PWork Normally, $g=9.81$ m/s², namely gravitational acceleration. Here, they multiplied this value with some other constant to take care of all the unit conversions. Very bad form if you ask me.

Be aware that the formulae for turn rate/radius in the PHAK are theoretical formulae that assume you are at, and can sustain, the specified speed and bank angle. These assumptions are generally false, and contibute to the false meme that the slower you fly, the tighter you can turn. What bank angle can you hold at 20 knots below 1 g stall speed?

The formulae should only be used to calculate turn rate/radius for a specified velocity and bank angle once you have verified that the aircraft can operate at that specified velocity and bank angle. Using the formulae to determine the best (highest), turn rate or smallest turn radius will not generate an accurate or meaningful result.

The AOA  is 15 degrees and pulling 9G for making the maximum performance turn in level turns  in F16. ( 22 degrees /sec)

They question is about turn rate, i.e. degrees per second, not AOA or max Gs.

Then 22degrees /sec

When you are asked for more info in a comment, and you have more to add, don't forget to add it to your answer. (I edited that in for you)